Exemplary embodiments of the present disclosure are directed to turbine blades and/or compressor blades for a gas turbine engine and methods for restraining a damper of a turbine blade and/or compressor blade.
A gas turbine engine includes a plurality of turbine blades and compressor blades each received in a slot of a disk. The blades are exposed to aerodynamic forces that can result in vibratory stresses. A seal damper or damper can be located under platforms of adjacent blades to reduce the vibratory response and provide frictional damping between the blades. The seal damper slides on an underside of the platforms. The seal damper is made of a material that is dissimilar from the material of the blades. When the vibratory motions of adjacent blades oppose each other (that is, occur out of phase), the seal damper slides to absorb the energy of vibration.
Seal dampers work by conforming to the underside of blade platforms to seal the mate-face gap between blades and provide frictional damping to suppress the vibratory response of the blades to excitations in the engine. These dampers are typically made of sheet metal and have been shown to readily conform to the underside of the platform when subjected to centrifugal loads in a high temperature environment due to their lack of stiffness out-of-plane.
Sometimes seal dampers will experience unintentional bulk tangential movement relative to the damper pocket due to the dynamic forces imposed on it by the rotation of the blades and the lack of sufficient restraint devices. To maximize damper efficiency, damper configurations are sought which minimize weight and maximize damper stiffness. Thus it is desirable to limit the number of weight increasing restraint devices on the damper (i.e. features which interlock with “damper tabs”, “damper nubs”, or some other feature of the under-platform geometry, or “bathtub” type designs that pre-conform to under-platform filleting).
Accordingly, it is desirable to a method and apparatus for restraining movement of a damper with respect to a blade platform.